The invention concerns dual-circuit, fluid pressure braking systems for motor vehicles controlled automatically as a function of the load.
There are presently known dual-circuit braking systems regulated with load-dependent brake pressure regulators, which are either pure compressed-air brake systems or compressed-air actuated hydraulic brake systems. In these systems, the brake pressure in the brake circuit of the rear axle is regulated as a function of the rear axle load, and the regulation of the brake pressure in the front axle braking circuit is accomplished via a line connection between the regulated rear axle braking circuit and an additional connection on the two-circuit brake valve or tandem master cylinder, whereby the brake pressure of the rear axle brake circuit is regulated as a function of the load and acts on a partial piston surface to which the brake pressure for the front axle braking circuit is applied.
In both cases, the dual-circuit brake pressure controllers possess five line connections so that these braking devices must be connected with five incoming and outgoing lines, namely the two lines from the compressed air source, the two lines to the axle brake circuits and the line from the regulated rear axle braking circuit.
The bulky design of these braking devices and the fact that the pressure lines must join in a confined area require a large amount of space for the assembly relative to the amount of space available in or around the cab.